Question Continuation
(a) Strings of length 6. Characters can be special characters, digits, or letters, with no repeated characters
(b) Strings of length 6. Characters can be special characters, digits, or letters, with no repeated characters. The first character can not be a special character
Answer:
(a) Number of selection = 2,763,633,600 ways
(b) Number of selection = 2,487,270,240 ways
Explanation:
Number of digits = 10
Letters = 26
Special Characters = 4
Total = 40
(a) Strings of length 6. Characters can be special characters, digits, or letters, with no repeated characters
Since there's no repetition and restrictions of characters
There are 40 ways of selecting the first character
There are 39 ways of selecting the second character
There are 38 ways of selecting the third character
There are 37 ways of selecting the fourth character
There are 36 ways of selecting the fifth character
There are 35 ways of selecting the sixth character
So, there are 40*39*38*37*36*35 ways of selecting a string of 6 characters
Number of selection = 2,763,633,600 ways
(b) Strings of length 6. Characters can be special characters, digits, or letters, with no repeated characters. The first character can not be a special character
Since there's no repetition and restrictions of characters and the first character must not be a special character
There are 36 ways of selecting the first character
There are 39 ways of selecting the second character
There are 38 ways of selecting the third character
There are 37 ways of selecting the fourth character
There are 36 ways of selecting the fifth character
There are 35 ways of selecting the sixth character
So, there are 36*39*38*37*36*35 ways of selecting a string of 6 characters
Number of selection = 2,487,270,240 ways